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Omidian M, Mostafavi-Pour Z, Asadi M, Sharifdini M, Nezafat N, Pouryousef A, Savardashtaki A, Taheri-Anganeh M, Mikaeili F, Sarkari B. Design and expression of a chimeric recombinant antigen (SsIR-Ss1a) for the serodiagnosis of human strongyloidiasis: Evaluation of performance, sensitivity, and specificity. PLoS Negl Trop Dis 2024; 18:e0012320. [PMID: 39008519 PMCID: PMC11271862 DOI: 10.1371/journal.pntd.0012320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 07/25/2024] [Accepted: 06/26/2024] [Indexed: 07/17/2024] Open
Abstract
BACKGROUND The sensitivity of parasitological and molecular methods is unsatisfactory for the diagnosis of strongyloidiasis, and serological techniques are remaining as the most effective diagnostic approach. The present study aimed to design and produce a chimeric recombinant antigen from Strongyloides stercoralis immunoreactive antigen (SsIR) and Ss1a antigens, using immune-informatics approaches, and evaluated its diagnostic performance in an ELISA system for the diagnosis of human strongyloidiasis. METHODOLOGY/PRINCIPAL FINDINGS The coding sequences for SsIR and Ss1a were selected from GenBank and were gene-optimized. Using bioinformatics analysis, the regions with the highest antigenicity that did not overlap with other parasite antigens were selected. The chimeric recombinant antigen SsIR- Ss1a, was constructed. The solubility and physicochemical properties of the designed construct were analyzed and its tertiary structures were built and evaluated. The construct was expressed into the pET-23a (+) expression vector and the optimized DNA sequences of SsIR-Ss1a (873 bp) were cloned into competent E. coli DH5α cells. Diagnostic performances of the produced recombinant antigen, along with a commercial kit were evaluated in an indirect ELISA system, using a panel of sera from strongyloidiasis patients and controls. The physicochemical and bioinformatics evaluations revealed that the designed chimeric construct is soluble, has a molecular with of 35 KDa, and is antigenic. Western blotting confirmed the immunoreactivity of the produced chimeric recombinant antigen with the sera of strongyloidiasis patients. The sensitivity and specificity of the indirect ELISA system, using the produced SsIR-Ss1a chimeric antigen, were found to be 93.94% (95% CI, 0.803 to 0.989) and 97.22% (95% CI, 0.921 to 0.992) respectively. CONCLUSIONS/SIGNIFICANCE The preliminary findings of this study suggest that the produced SsIR-Ss1a chimeric antigen shows promise in the diagnosis of human strongyloidiasis. However, these results are based on a limited panel of samples, and further research with a larger sample size is necessary to confirm its accuracy. The construct has potential as an antigen in the ELISA system for the serological diagnosis of this neglected parasitic infection, but additional validation is required.
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Affiliation(s)
- Mostafa Omidian
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zohreh Mostafavi-Pour
- Recombinant Proteins Laboratory, Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Marzieh Asadi
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences Shiraz, Iran
| | - Meysam Sharifdini
- Department of Medical Parasitology and Mycology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Navid Nezafat
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Pouryousef
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir Savardashtaki
- Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences Shiraz, Iran
| | - Mortaza Taheri-Anganeh
- Cellular and Molecular Research Center, Cellular and Molecular Medicine Research Institute, Urmia University of Medical Sciences, Urmia, Iran
| | - Fattaneh Mikaeili
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Bahador Sarkari
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Prato M, Tamarozzi F, Tais S, Rizzi E, Mazzi C, Buonfrate D. Evaluation of the SsIR/NIE recombinant antigen ELISA for the follow up of patients infected by Strongyloides stercoralis: a diagnostic study. Parasitology 2024; 151:295-299. [PMID: 38185819 PMCID: PMC11007275 DOI: 10.1017/s0031182024000027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/06/2023] [Accepted: 12/19/2023] [Indexed: 01/09/2024]
Abstract
Some serology assays demonstrated useful for post-treatment monitoring of Strongyloides stercoralis infection. Serology frequently has low specificity, which might be improved by the use of recombinant antigens. The Strongy Detect ELISA is based on 2 recombinant antigens (SsIR and NIE) and proved good accuracy. Aim of this study was to evaluate the performance of this test for the post-treatment monitoring of strongyloidiasis. We tested 38 paired sera, with matched fecal tests results, stored in our biobank and originating from a randomized controlled trial. At baseline, all patients tested positive for at least 1 fecal assay among PCR, direct stool microscopy and agar plate culture. Patients were re-tested with both serology and fecal assays 12 months after treatment. Primary outcome was the relative reduction in optical density (OD) between baseline and follow up. We observed that about 95% samples showed a reduction between pre and post-treatment OD, with a median relative reduction of 93.9% (IQR 77.3%–98.1%). In conclusion, the test proved reliable for post-treatment monitoring. However, some technical issues, including that the threshold for positivity has not be predefined, and that a substantial number of samples showed overflow signals, need to be fixed to permit use in routine practice.
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Affiliation(s)
- Marco Prato
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar di Valpolicella, Italy
| | - Francesca Tamarozzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar di Valpolicella, Italy
| | - Stefano Tais
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar di Valpolicella, Italy
| | - Eleonora Rizzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar di Valpolicella, Italy
| | - Cristina Mazzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar di Valpolicella, Italy
| | - Dora Buonfrate
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Negrar di Valpolicella, Italy
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3
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Wongphutorn P, Noordin R, Anuar NS, Worasith C, Kopolrat KY, Homwong C, Tippayawat P, Techasen A, Pitaksakurat O, Sithithaworn J, Eamudomkarn C, Sithithaworn P. Examination of Diagnostic Performance of New IgG4 Rapid Test Compared with IgG- and IgG4-ELISAs to Investigate Epidemiology of Strongyloidiasis in Northeast Thailand. Am J Trop Med Hyg 2024; 110:254-262. [PMID: 38190756 PMCID: PMC10859814 DOI: 10.4269/ajtmh.23-0518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 10/16/2023] [Indexed: 01/10/2024] Open
Abstract
Strongyloidiasis, caused by Strongyloides stercoralis, is a neglected tropical disease with a global distribution. The infection can be fatal in immunocompromised individuals, and accurate diagnosis leading to timely treatment can save lives. Serodiagnosis is a sensitive method for diagnosis and is recommended for screening high-risk individuals. A point-of-care rapid test will facilitate the screening activities, especially in low-resource settings. This study aims to apply a new IgG4 immunochromatographic test using S. stercoralis recombinant antigen (SsRapid® cassette test) and to compare it with in-house IgG and IgG4 enzyme-linked immunosorbent assays (IgG- and IgG4-ELISAs) using native Strongyloides ratti antigen to investigate the epidemiology of strongyloidiasis in northeast Thailand. A total of 300 people participated, with 136 males and 164 females of a similar mean age. The reference tests were fecal examinations using the formalin-ethyl acetate concentration technique and an agar plate culture technique. The prevalence of S. stercoralis determined by SsRapid (81.7%) was significantly higher than that by fecal examinations (43.3%) or by antibody detection by IgG-ELISA (53.0%) or IgG4-ELISA (44.0%). The diagnostic sensitivities of SsRapid, IgG-ELISA, and IgG4-ELISA were found to be 93.9%, 77.7%, and 63.1%, respectively. The rate of positive tests by the SsRapid was significantly correlated to the levels of Strongyloides-specific IgG4 and IgG antibodies. By all diagnostic methods, male participants had a significantly higher prevalence of strongyloidiasis than females. Age was significantly associated with the concentration of specific serum IgG but not with the SsRapid grading score. In conclusion, SsRapid was shown to be a sensitive and valuable diagnostic test for the epidemiology study of strongyloidiasis.
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Affiliation(s)
| | - Rahmah Noordin
- Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Penang, Malaysia
| | - Nor Suhada Anuar
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, Penang, Malaysia
| | - Chanika Worasith
- Department of Adult Nursing, Faculty of Nursing, Khon Kaen University, Khon Kaen, Thailand
| | - Kulthida Y. Kopolrat
- Faculty of Public Health, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon, Thailand
| | - Chutima Homwong
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
| | | | - Anchalee Techasen
- Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Opal Pitaksakurat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | | | - Chatanun Eamudomkarn
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Paiboon Sithithaworn
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
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Buonfrate D, Bradbury RS, Watts MR, Bisoffi Z. Human strongyloidiasis: complexities and pathways forward. Clin Microbiol Rev 2023; 36:e0003323. [PMID: 37937980 PMCID: PMC10732074 DOI: 10.1128/cmr.00033-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 08/11/2023] [Indexed: 11/09/2023] Open
Abstract
Strongyloidiasis is a World Health Organization neglected tropical disease usually caused by Strongyloides stercoralis, a parasitic worm with a complex life cycle. Globally, 300-600 million people are infected through contact with fecally contaminated soil. An autoinfective component of the life cycle can lead to chronic infection that may be asymptomatic or cause long-term symptoms, including malnourishment in children. Low larval output can limit the sensitivity of detection in stool, with serology being effective but less sensitive in immunocompromise. Host immunosuppression can trigger catastrophic, fatal hyperinfection/dissemination, where large numbers of larvae pierce the bowel wall and disseminate throughout the organs. Stable disease is effectively treated by single-dose ivermectin, with disease in immunocompromised patients treated with multiple doses. Strategies for management include raising awareness, clarifying zoonotic potential, the development and use of effective diagnostic tests for epidemiological studies and individual diagnosis, and the implementation of treatment programs with research into therapeutic alternatives and medication safety.
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Affiliation(s)
- Dora Buonfrate
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Richard S. Bradbury
- School of Health and Life Sciences, Federation University Australia, Berwick, Victoria, Australia
| | - Matthew R. Watts
- Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research – New South Wales Health Pathology and Sydney Institute for Infectious Diseases, Westmead Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Zeno Bisoffi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
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Boonroumkaew P, Sadaow L, Janwan P, Rodpai R, Sanpool O, Buadee P, Suprom C, Thanchomnang T, Intapan PM, Maleewong W. Improved diagnostic sensitivity of human strongyloidiasis using point-of-care mixed recombinant antigen-based immunochromatography. Parasite 2023; 30:60. [PMID: 38099622 PMCID: PMC10723528 DOI: 10.1051/parasite/2023063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/25/2023] [Indexed: 12/17/2023] Open
Abstract
Strongyloidiasis is a neglected tropical disease that can cause fatal complications due to hyperinfection and disseminated strongyloidiasis in immunocompromised patients. We used two Strongyloides stercoralis recombinant antigenic proteins, L3NieAg.01 (NIE) and IgG-immunoreactive antigen (SsIR), to develop the recombinant antigen-based immunochromatography test (ICT) kit. We constructed and compared kits using either the NIE (NIE ICT kit) or the SsIR (SsIR ICT kit) antigens and a kit using a mixture of both (NIE-SsIR ICT kit) for detection of anti-Strongyloides IgG antibody in human serum samples. Serum samples from normal healthy individuals (Group I, n = 40), proven strongyloidiasis patients (Group II, n = 100), and those with other parasitic infections (Group III, n = 154) were evaluated. Sensitivity and specificity were 81.0% and 84.0% for the NIE ICT kit, 89.0% and 83.5% for the SsIR ICT kit, and 95.0% and 90.2% for the NIE-SsIR ICT kit, respectively. The NIE-SsIR ICT kit provided the best diagnostic results; it can supplement stool examination for clinical diagnosis and can be used to screen for asymptomatic S. stercoralis infection in people at risk in endemic areas. The NIE-SsIR ICT kit can also be used in large-scale sero-epidemiological investigations in endemic areas without the need for additional facilities or ancillary supplies.
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Affiliation(s)
- Patcharaporn Boonroumkaew
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Lakkhana Sadaow
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Penchom Janwan
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
- Department of Medical Technology, School of Allied Health Sciences, Walailak University 80161 Nakhon Si Thammarat Thailand
- Hematology and Transfusion Science Research Center, Walailak University 80161 Nakhon Si Thammarat Thailand
| | - Rutchanee Rodpai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Oranuch Sanpool
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Punyisa Buadee
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Chanida Suprom
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Tongjit Thanchomnang
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
- Faculty of Medicine, Mahasarakham University 44000 Maha Sarakham Thailand
| | - Pewpan M. Intapan
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
| | - Wanchai Maleewong
- Department of Parasitology, Faculty of Medicine, Khon Kaen University 40002 Khon Kaen Thailand
- Mekong Health Science Research Institute, Khon Kaen University 40002 Khon Kaen Thailand
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Wongphutorn P, Worasith C, Kopolrat KY, Homwong C, Sithithaworn J, Eamudomkarn C, Techasen A, Tippayawat P, Pitaksakurat O, Hongsrichan N, Crellen T, Sithithaworn P. Diagnostic performance of Strongyloides-specific IgG4 detection in urine for diagnosis of human strongyloidiasis. Parasit Vectors 2023; 16:298. [PMID: 37641157 PMCID: PMC10464225 DOI: 10.1186/s13071-023-05935-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Detection of parasite-specific IgG in urine is a sensitive method for diagnosis of strongyloidiasis and gives similar accuracy to serum IgG. However, there are no data concerning detection of IgG subclass in urine. To further explore the utility of diagnosis from urine samples, we evaluated the diagnostic performance of IgG4 in urine compared with parasitological and other immunological methods. METHODS The urine and sera included proven strongyloidiasis (group 1, n = 93), other parasitic infections (group 2, n = 40) and parasite negatives (group 3, n = 93). The performance of Strongyloides-specific IgG4 in urine for diagnosis of strongyloidiasis using fecal examinations as the reference standard was assessed. RESULTS With fecal examination as a gold standard, Strongyloides-specific IgG4 in urine had 91.4% sensitivity and 93.2% specificity while serum IgG4 had 93.6% sensitivity and 91.0% specificity. IgG4 in both urine and serum had almost perfect diagnostic agreements with fecal examination (Cohen's kappa coefficient was > 0.8). Cross-reactivity to Opisthorchis viverrini and Taenia spp. of IgG4 in urine were 7.5% and 12.5% in serum. Concurrent analyses of total IgG in urine and serum showed that the sensitivities (97.9-100%) and specificities (88.7-91.0%) were similar (P > 0.05). The sensitivity for parasitological examination by the formalin-ethyl acetate concentration technique (FECT) was 49.5% and that for agar plate culture technique (APC) it was 92.6%. CONCLUSION Our findings showed that specific IgG4 detection in urine yielded similar diagnostic performance to the same biomarkers in serum. This suggests that accurate diagnosis of strongyloidiasis can be performed using urine samples and IgG4 is a valid choice of diagnostic marker. Further assessment is required to assess the utility of urine IgG4 for measuring the response treatment in strongyloidiasis.
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Affiliation(s)
| | - Chanika Worasith
- Department of Adult Nursing, Faculty of Nursing, Khon Kaen University, Khon Kaen, Thailand
| | - Kulthida Y Kopolrat
- Faculty of Public Health, Kasetsart University Chalermphrakiat Sakon Nakhon Province Campus, Sakon Nakhon, Thailand
| | - Chutima Homwong
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand
| | | | - Chatanun Eamudomkarn
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Anchalee Techasen
- Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | | | - Opal Pitaksakurat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Nuttanan Hongsrichan
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Thomas Crellen
- School of Biodiversity One Health and Veterinary Medicine, University of Glasgow, Graham Kerr Building, Glasgow, UK
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Sir Graeme Davies Building, Glasgow, UK
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Paiboon Sithithaworn
- Cholangiocarcinoma Research Institute, Khon Kaen University, Khon Kaen, Thailand.
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
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Marlais T, Bickford-Smith J, Talavera-López C, Le H, Chowdhury F, Miles MA. A comparative 'omics' approach for prediction of candidate Strongyloides stercoralis diagnostic coproantigens. PLoS Negl Trop Dis 2023; 17:e0010777. [PMID: 37068106 PMCID: PMC10138266 DOI: 10.1371/journal.pntd.0010777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 04/27/2023] [Accepted: 04/03/2023] [Indexed: 04/18/2023] Open
Abstract
Human infection with the intestinal nematode Strongyloides stercoralis is persistent unless effectively treated, and potentially fatal in immunosuppressed individuals. Epidemiological data are lacking, partially due to inadequate diagnosis. A rapid antigen detection test is a priority for population surveillance, validating cure after treatment, and for screening prior to immunosuppression. We used a targeted analysis of open access 'omics' data sets and used online predictors to identify S. stercoralis proteins that are predicted to be present in infected stool, Strongyloides-specific, and antigenic. Transcriptomic data from gut and non-gut dwelling life cycle stages of S. stercoralis revealed 328 proteins that are differentially expressed. Strongyloides ratti proteomic data for excreted and secreted (E/S) proteins were matched to S. stercoralis, giving 1,057 orthologues. Five parasitism-associated protein families (SCP/TAPS, prolyl oligopeptidase, transthyretin-like, aspartic peptidase, acetylcholinesterase) were compared phylogenetically between S. stercoralis and outgroups, and proteins with least homology to the outgroups were selected. Proteins that overlapped between the transcriptomic and proteomic datasets were analysed by multiple sequence alignment, epitope prediction and 3D structure modelling to reveal S. stercoralis candidate peptide/protein coproantigens. We describe 22 candidates from seven genes, across all five protein families for further investigation as potential S. stercoralis diagnostic coproantigens, identified using open access data and freely-available protein analysis tools. This powerful approach can be applied to many parasitic infections with 'omic' data to accelerate development of specific diagnostic assays for laboratory or point-of-care field application.
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Affiliation(s)
- Tegwen Marlais
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jack Bickford-Smith
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Carlos Talavera-López
- Institute of Computational Biology, Computational Health Centre, Helmholtz Munich, Neuherberg, Germany
| | - Hai Le
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Fatima Chowdhury
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael A Miles
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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8
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Chan AHE, Thaenkham U. From past to present: opportunities and trends in the molecular detection and diagnosis of Strongyloides stercoralis. Parasit Vectors 2023; 16:123. [PMID: 37041645 PMCID: PMC10088203 DOI: 10.1186/s13071-023-05763-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/30/2023] [Indexed: 04/13/2023] Open
Abstract
Strongyloides stercoralis is a soil-transmitted helminth that is mainly found in the tropical and subtropical regions and affects approximately 600 million people globally. The medical importance of strongyloidiasis lies in its capacity to remain asymptomatic and chronically unnoticed until the host is immunocompromised. Additionally, in severe strongyloidiasis, hyperinfection syndrome and larva dissemination to various organs can occur. Parasitological techniques such as Baermann-Moraes and agar plate culture to detect larvae in stool samples are the current gold standard. However, the sensitivity might be inadequate, especially with reduced worm burden. Complementing parasitological techniques, immunological techniques including immunoblot and immunosorbent assays are employed, with higher sensitivity. However, cross-reactivity to other parasites may occur, hampering the assay's specificity. Recently, advances in molecular techniques such as polymerase chain reaction and next-generation sequencing technology have provided the opportunity to detect parasite DNA in stool, blood, and environmental samples. Molecular techniques, known for their high sensitivity and specificity, have the potential to circumvent some of the challenges associated with chronicity and intermittent larval output for increased detection. Here, as S. stercoralis was recently included by the World Health Organization as another soil-transmitted helminth targeted for control from 2021 to 2030, we aimed to present a review of the current molecular techniques for detecting and diagnosing S. stercoralis in a bid to consolidate the molecular studies that have been performed. Upcoming molecular trends, especially next-generation sequencing technologies, are also discussed to increase the awareness of its potential for diagnosis and detection. Improved and novel detection methods can aid in making accurate and informed choices, especially in this era where infectious and non-infectious diseases are increasingly commonplace.
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Affiliation(s)
| | - Urusa Thaenkham
- Department of Helminthology, Mahidol University, Bangkok, Thailand
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Tamarozzi F, Guevara ÁG, Anselmi M, Vicuña Y, Prandi R, Marquez M, Vivero S, Robinzón Huerlo F, Racines M, Mazzi C, Denwood M, Buonfrate D. Accuracy, acceptability, and feasibility of diagnostic tests for the screening of Strongyloides stercoralis in the field (ESTRELLA): a cross-sectional study in Ecuador. Lancet Glob Health 2023; 11:e740-e748. [PMID: 36972722 DOI: 10.1016/s2214-109x(23)00108-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/06/2023] [Accepted: 02/16/2023] [Indexed: 03/29/2023]
Abstract
BACKGROUND WHO recommends the implementation of control programmes for strongyloidiasis, a neglected tropical disease caused by Strongyloides stercoralis. Specific recommendations on the diagnostic test or tests to be used for such programmes have yet to be defined. The primary objective of this study was to estimate the accuracy of five tests for strongyloidiasis. Secondary objectives were to evaluate acceptability and feasibility of use in an endemic area. METHODS The ESTRELLA study was a cross-sectional study for which we enrolled school-age children living in remote villages of Ecuador. Recruitment took place in two periods (Sept 9-19, 2021, and April 18-June 11, 2022). Children supplied one fresh stool sample and underwent blood collection via finger prick. Faecal tests were a modified Baermann method and an in-house real-time PCR test. Antibody assays were a recombinant antigen rapid diagnostic test; a crude antigen-based ELISA (Bordier ELISA); and an ELISA based on two recombinant antigens (Strongy Detect ELISA). A Bayesian latent class model was used to analyse the data. FINDINGS 778 children were enrolled in the study and provided the required samples. Strongy Detect ELISA had the highest sensitivity at 83·5% (95% credible interval 73·8-91·8), while Bordier ELISA had the highest specificity (100%, 99·8-100). Bordier ELISA plus either PCR or Baermann had the best performance in terms of positive and negative predictive values. The procedures were well accepted by the target population. However, study staff found the Baermann method cumbersome and time-consuming and were concerned about the amount of plastic waste produced. INTERPRETATION The combination of Bordier ELISA with either faecal test performed best in this study. Practical aspects (including costs, logistics, and local expertise) should, however, also be taken into consideration when selecting tests in different contexts. Acceptability might differ in other settings. FUNDING Italian Ministry of Health. TRANSLATION For the Spanish translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Francesca Tamarozzi
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Ángel G Guevara
- Instituto de Investigación en Biomedicina, carrera de Medicina, Universidad Central del Ecuador (UCE), Quito, Ecuador
| | - Mariella Anselmi
- Centro de Epidemiologia Comunitaria y Medicina Tropical (CECOMET), Esmeraldas, Ecuador
| | - Yosselin Vicuña
- Instituto de Investigación en Biomedicina, carrera de Medicina, Universidad Central del Ecuador (UCE), Quito, Ecuador
| | - Rosanna Prandi
- Centro de Epidemiologia Comunitaria y Medicina Tropical (CECOMET), Esmeraldas, Ecuador
| | - Monica Marquez
- Centro de Epidemiologia Comunitaria y Medicina Tropical (CECOMET), Esmeraldas, Ecuador
| | - Sandra Vivero
- Instituto de Investigación en Biomedicina, carrera de Medicina, Universidad Central del Ecuador (UCE), Quito, Ecuador
| | | | - Marcia Racines
- Instituto de Investigación en Biomedicina, carrera de Medicina, Universidad Central del Ecuador (UCE), Quito, Ecuador
| | - Cristina Mazzi
- Clinical Research Unit, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Dora Buonfrate
- Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy.
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10
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Dishnica K, Piubelli C, Manfredi M, Kondaveeti RT, Longoni SS, Degani M, Buonfrate D, Giorgetti A, Tiberti N. Novel insights into the somatic proteome of Strongyloides stercoralis infective third-stage larvae. Parasit Vectors 2023; 16:45. [PMID: 36721249 PMCID: PMC9890704 DOI: 10.1186/s13071-023-05675-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 01/18/2023] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Strongyloidiasis is a neglected tropical disease affecting an estimated 600 million people, particularly in resource-limited settings. The infection can persist lifelong due to unusual auto-infective cycle of Strongyloides stercoralis. The lack of a diagnostic gold standard and limited knowledge of the mechanisms underpinning this chronic infection are key issues in disease management. To date, only a few proteomics studies have been conducted to elucidate the molecular mechanisms associated with Strongyloides parasitism or to highlight novel immunological markers, with the result that our knowledge of S. stercoralis proteome remains limited. This study aims at expanding the characterization of S. stercoralis infective larvae (iL3) in order to further explore the mechanisms of parasitism and to highlight possible novel targets for serodiagnosis. METHODS iL3 obtained from an infected subject were analysed by high-throughput tandem mass spectrometry. To achieve a more comprehensive characterization of the iL3 proteome we analysed the experimental dataset using an automatic search strategy combined with manual annotation, which included gene ontology (GO) analysis, InterPro annotation, assessment of the homology with Homo sapiens and other pathogens of clinical importance and B-cell epitope prediction. RESULTS Our pipeline identified 430 S. stercoralis proteins, 187 (43%) of which were uncharacterized. Oxidoreductases and peptidases were amongst the most represented protein categories, as highlighted by molecular function GO analyses, while membrane and mitochondrial proteins were the most represented cellular component GO categories. A high proportion of proteins bearing the CAP, SCP or thioredoxin domain or belonging to cysteine-rich secretory, transthyretin-like or peptidase protein families were also identified. Additionally, we highlighted nine proteins displaying low homology with H. sapiens or other related pathogens and bearing amino acid sequences with immunogenic properties. CONCLUSIONS Our comprehensive description and annotation of the S. stercoralis iL3 proteome contribute to expanding the 'omics characterization of this parasite and provide experimental evidence on the most represented proteins associated with S. stercoralis parasitism, as inferred from genomic and transcriptomic data. Moreover, novel candidate immunogenic proteins to be evaluated as novel serological diagnostic markers are highlighted.
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Affiliation(s)
- Klevia Dishnica
- grid.5611.30000 0004 1763 1124Department of Biotechnology, University of Verona, Verona, Italy
| | - Chiara Piubelli
- grid.416422.70000 0004 1760 2489Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
| | - Marcello Manfredi
- grid.16563.370000000121663741Department of Translational Medicine, University of Piemonte Orientale, Novara, Italy
| | - Ravi Teja Kondaveeti
- grid.416422.70000 0004 1760 2489Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
| | - Silvia Stefania Longoni
- grid.416422.70000 0004 1760 2489Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
| | - Monica Degani
- grid.416422.70000 0004 1760 2489Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
| | - Dora Buonfrate
- grid.416422.70000 0004 1760 2489Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
| | - Alejandro Giorgetti
- grid.5611.30000 0004 1763 1124Department of Biotechnology, University of Verona, Verona, Italy
| | - Natalia Tiberti
- grid.416422.70000 0004 1760 2489Department of Infectious, Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
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11
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Buonfrate D, Tamarozzi F, Paradies P, Watts MR, Bradbury RS, Bisoffi Z. The diagnosis of human and companion animal Strongyloides stercoralis infection: Challenges and solutions. A scoping review. ADVANCES IN PARASITOLOGY 2022; 118:1-84. [PMID: 36088083 DOI: 10.1016/bs.apar.2022.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Strongyloidiasis is the infection caused by soil-transmitted nematodes of Strongyloides species, infecting humans and some animals. Strongyloides stercoralis is the species with most clinical and epidemiological relevance in humans and dogs, due to its high prevalence and its capacity of inducing a life-threatening hyperinfection. Diagnosis of strongyloidiasis is challenging, due to the absence of a single reference standard test with high sensitivity and specificity, which also hampers the estimation of the accuracy of other diagnostic tests. In this chapter, we review the deployment and performance of the parasitological, immunological, molecular tests for the diagnosis of strongyloidiasis in humans and in dogs. Further, we comment the available evidence from genotyping studies that have addressed the zoonotic potential of S. stercoralis. Finally, we discuss the use of different diagnostic methods in relation to the purpose (i.e., screening, individual diagnosis, inclusion in a clinical trial) and the setting (endemic/non-endemic areas) and report the accuracy figures reported by systematic reviews on either parasitological, serological or molecular techniques published in literature.
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Affiliation(s)
- Dora Buonfrate
- Department of Infectious Tropical diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy.
| | - Francesca Tamarozzi
- Department of Infectious Tropical diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy
| | - Paola Paradies
- Department of Emergency and Organs Transplantation, Veterinary Section, Campus of Veterinary Medicine, University of Bari, Bari, Italy
| | - Matthew R Watts
- Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research - New South Wales Health Pathology and Sydney Institute for Infectious Diseases, Westmead Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Richard S Bradbury
- School of Health and Life Sciences, Federation University Australia, Berwick, VC, Australia
| | - Zeno Bisoffi
- Department of Infectious Tropical diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy; Department of Diagnostics and Public Health, University of Verona, Verona, Italy
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12
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Santano R, Rubio R, Grau-Pujol B, Escola V, Muchisse O, Cuamba I, Vidal M, Ruiz-Olalla G, Aguilar R, Gandasegui J, Demontis M, Jamine JC, Cossa A, Sacoor C, Cano J, Izquierdo L, Chitnis CE, Coppel RL, Chauhan V, Cavanagh D, Dutta S, Angov E, van Lieshout L, Zhan B, Muñoz J, Dobaño C, Moncunill G. Evaluation of antibody serology to determine current helminth and Plasmodium falciparum infections in a co-endemic area in Southern Mozambique. PLoS Negl Trop Dis 2022; 16:e0010138. [PMID: 35727821 PMCID: PMC9212154 DOI: 10.1371/journal.pntd.0010138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022] Open
Abstract
Background Soil-transmitted helminths (STH), Schistosoma spp. and Plasmodium falciparum are parasites of major public health importance and co-endemic in many sub-Saharan African countries. Management of these infections requires detection and treatment of infected people and evaluation of large-scale measures implemented. Diagnostic tools are available but their low sensitivity, especially for low intensity helminth infections, leaves room for improvement. Antibody serology could be a useful approach thanks to its potential to detect both current infection and past exposure. Methodology We evaluated total IgE responses and specific-IgG levels to 9 antigens from STH, 2 from Schistosoma spp., and 16 from P. falciparum, as potential markers of current infection in a population of children and adults from Southern Mozambique (N = 715). Antibody responses were measured by quantitative suspension array Luminex technology and their performance was evaluated by ROC curve analysis using microscopic and molecular detection of infections as reference. Principal findings IgG against the combination of EXP1, AMA1 and MSP2 (P. falciparum) in children and NIE (Strongyloides stercoralis) in adults and children had the highest accuracies (AUC = 0.942 and AUC = 0.872, respectively) as markers of current infection. IgG against the combination of MEA and Sm25 (Schistosoma spp.) were also reliable markers of current infection (AUC = 0.779). In addition, IgG seropositivity against 20 out of the 27 antigens in the panel differentiated the seropositive endemic population from the non-endemic population, suggesting a possible role as markers of exposure although sensitivity could not be assessed. Conclusions We provided evidence for the utility of antibody serology to detect current infection with parasites causing tropical diseases in endemic populations. In addition, most of the markers have potential good specificity as markers of exposure. We also showed the feasibility of measuring antibody serology with a platform that allows the integration of control and elimination programs for different pathogens. Parasitic worms and Plasmodium falciparum, the causal agent of malaria, are among the most relevant parasitic diseases of our time and efforts are under way for their control and, ultimately, elimination. An accurate diagnosis is relevant for case management, but also allows calculating the prevalence and evaluating the effectiveness of treatment and control measures. Unfortunately, current diagnostic methods for parasitic worms are not optimal and many infections remain undetected. As for P. falciparum, current diagnostic techniques are satisfactory but do not allow for ascertaining exposure, which is relevant for evaluating control measures. Here we investigated the utility of measuring antibodies to these parasites as a diagnostic method. Our results indicate that it is possible to detect current infection with parasitic worms and P. falciparum using antibody detection with a moderate to high accuracy. We also show that antibodies against the antigens in this study have potential as markers of exposure. Importantly, we used a platform that allows for the simultaneous detection of immunoglobulins to different parasites, which would be extremely useful as a tool to integrate control and elimination programs for several pathogens.
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Affiliation(s)
- Rebeca Santano
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- * E-mail: (RS); (CD); (GM)
| | - Rocío Rubio
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Berta Grau-Pujol
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Fundación Mundo Sano, Buenos Aires, Argentina
| | - Valdemiro Escola
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Osvaldo Muchisse
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Inocência Cuamba
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Marta Vidal
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Gemma Ruiz-Olalla
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Ruth Aguilar
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Javier Gandasegui
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Maria Demontis
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | | | - Anélsio Cossa
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Charfudin Sacoor
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Jorge Cano
- Communicable and Non-communicable Diseases Cluster (UCN), WHO Regional Office for Africa, Brazzaville, Republic of Congo
| | - Luis Izquierdo
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Chetan E. Chitnis
- Malaria Parasite Biology and Vaccines Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, Paris, France
| | - Ross L. Coppel
- Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Virander Chauhan
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - David Cavanagh
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Sheetij Dutta
- Walter Reed Army Institute of Research (WRAIR), Silver Spring, Maryland, United States of America
| | - Evelina Angov
- Walter Reed Army Institute of Research (WRAIR), Silver Spring, Maryland, United States of America
| | - Lisette van Lieshout
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Bin Zhan
- Baylor College of Medicine (BCM), Houston, Texas, United States of America
| | - José Muñoz
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Carlota Dobaño
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
- * E-mail: (RS); (CD); (GM)
| | - Gemma Moncunill
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
- * E-mail: (RS); (CD); (GM)
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13
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Tamarozzi F, Longoni SS, Mazzi C, Rizzi E, Noordin R, Buonfrate D. The accuracy of a recombinant antigen immunochromatographic test for the detection of Strongyloides stercoralis infection in migrants from sub-Saharan Africa. Parasit Vectors 2022; 15:142. [PMID: 35461265 PMCID: PMC9034504 DOI: 10.1186/s13071-022-05249-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/21/2022] [Indexed: 12/02/2022] Open
Abstract
Background Strongyloidiasis, a nematode infection which is mainly caused by Strongyloides stercoralis in humans, can lead to a fatal syndrome in immunocompromised individuals. Its diagnosis is challenging due to the absence of a diagnostic gold standard. The infection is highly prevalent in migrants from endemic countries in tropical and subtropical areas, and a rapid diagnostic test would be helpful for screening purposes. The aim of this study was to estimate the accuracy of a novel immunochromatographic test (ICT) for the diagnosis of S. stercoralis infection. Methods A single-centre diagnostic accuracy study was undertaken using well-characterized frozen sera available from the biobank of a referral hospital for parasitic diseases in Italy. The included sera were from migrants from sub-Saharan Africa, and matching results were available for agar plate culture and/or polymerase chain reaction for S. stercoralis; moreover, the results of both a commercial enzyme-linked immunosorbent assay test and an in-house immunofluorescence test for strongyloidiasis were made available. Laboratory staff who read the ICT results were blinded as regards the results of the other tests. Two readers independently read the ICT, and a third one was involved when results were discrepant. The accuracy of the ICT was assessed both against the results of the panel of faecal tests and by latent class analysis (LCA). Results Agreement between the readers was excellent [Cohen’s κ = 92.7%, 95% confidence interval (CI) 88.3–97.1%]. When assessed against the results of the faecal tests, the sensitivity and specificity of the ICT were 82.4% (95% CI 75.7–89.0%) and 73.8% (95% CI 66.8–80.9%), respectively. According to the LCA, the sensitivity and specificity were 86.3% (95% CI 80.1–92.5%) and 73.9% (95% CI 67.0–80.8%), respectively. Conclusions The results of the ICT demonstrated ease of interpretation. The accuracy proved good, though the sensitivity might be further improved for screening purposes. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05249-z.
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Affiliation(s)
- Francesca Tamarozzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, 37024, Negrar, Verona, Italy
| | - Silvia Stefania Longoni
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, 37024, Negrar, Verona, Italy
| | - Cristina Mazzi
- Clinical Research Unit, IRCCS Sacro Cuore Don Calabria Hospital, 37024, Negrar, Verona, Italy
| | - Eleonora Rizzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, 37024, Negrar, Verona, Italy
| | - Rahmah Noordin
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800, Penang, Malaysia
| | - Dora Buonfrate
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, 37024, Negrar, Verona, Italy.
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14
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Sears WJ, Nutman TB. Strongy Detect: Preliminary Validation of a Prototype Recombinant Ss-NIE/Ss-IR Based ELISA to Detect Strongyloides stercoralis Infection. PLoS Negl Trop Dis 2022; 16:e0010126. [PMID: 35077470 PMCID: PMC8789141 DOI: 10.1371/journal.pntd.0010126] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/22/2021] [Indexed: 11/18/2022] Open
Abstract
Background
Strongyloides stercoralis (Ss) is the etiological agent of strongyloidiasis, a neglected tropical disease of global concern. Laboratory diagnosis of strongyloidiasis is most often based on detection of antibodies against antigens in an enzyme linked immunosorbent assay (ELISA). Herein, we report a preliminary validation study of newly developed IgG4- and/or IgG- based ELISAs to detect strongyloidiasis (Strongy Detect, InBios) incorporating a cocktail of 2 previously described recombinant antigens, Ss-NIE and Ss-IR.
Methods
The sensitivity and specificity were determined by using the assay in 150 cryopreserved serum samples from humans known to be Ss infected (n = 74), helminth uninfected (n = 47), or infected with a helminth other than Ss [n = 29). The treatment associated dynamics of antibody detection were then assessed using 35 paired samples obtained before and after definitive therapy.
Results
The IgG and IgG4 assays were 99% and 96% sensitive, respectively, and 99% and 100% specific, respectively. Neither the IgG or IgG4 assay showed cross reactions with sera from those infected with other helminths. Although ELISA values did decline post-treatment few returned to levels below the cutoff for infection.
Conclusion
Strongy Detect is the most sensitive and specific commercialized immunoassay for detection of strongyloidiasis. The assay remains positive for greater than a year post-treatment.
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Affiliation(s)
- William J. Sears
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
- * E-mail:
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, United States of America
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15
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Concentration of urine samples improves sensitivity in detection of Strongyloides-specific IgG antibody in urine for diagnosis of strongyloidiasis. J Clin Microbiol 2021; 60:e0145421. [PMID: 34705534 DOI: 10.1128/jcm.01454-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Detection of IgG in urine is an efficient method comparable to that in serum for diagnosis of strongyloidiasis but effects of daily variation in urine dilution on diagnostic accuracy is not clearly known. This study evaluated effects of urine concentration on detection of parasite-specific IgG by urine enzyme-linked immunosorbent assay (ELISA), particularly in individuals with border-line results or false-negative diagnosis. Optimal concentration conditions were established by comparing Strongyloides-specific IgG antibody levels between unconcentrated and concentrated urine in participants with different infection intensities, namely healthy control (HC), low-negative (LN), high-negative (HN) and low-positive (LP) groups. The optimal condition was selected and validated in a field-trial study. The final urine concentration protocol required centrifugation at 4,000 g at 4°C for 10 mins using the Amicon® concentrator tube. This protocol was validated in groups of participants with varying diagnoses according to urine ELISA and fecal examination (n=148). The concentrated-urine ELISA increased the proportion of positive results in the LN group by 68.2% and by 100% in the HN group. Significantly elevated IgG antibody levels were seen in the LP group. In the group that was false negative by urine ELISA but positive by fecal examination (n=28), concentrated-urine ELISA yielded 100% positive results. Overall, the frequency estimates of S. stercoralis were 23.6% by fecal culture, 27% by standard urine ELISA and 90.5% by concentrated-urine ELISA. Concentration of urine samples prior to analysis by ELISA improved the sensitivity for diagnosis and is potentially useful in diagnosis of strongyloidiasis in immunocompromised individuals or in low-prevalence areas.
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